JP2003084134A - Method for manufacturing polarized beam splitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polarized beam splitter with high productivity and high flatness with which an overcoat layer consisting of an isotropic adhesive to adhere a counter transparent substrate and a transparent substrate can be made uniform with desired thickness. SOLUTION: A thickness regulating member 15 to regulate the thickness of the overcoat layer made of the isotropic adhesive 17 to adhere the counter transparent substrate 18 and the transparent substrate 8 is preliminarily disposed in the outside of the device where a grating 12 is formed. Thus, even when the isotropic adhesive having low viscosity is used, the overcoat layer can be easily made uniform with desired thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a polarization separation element having high productivity and high reliability.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 63-314502 has been proposed as a polarization separation element which can be manufactured at a low cost by a simple process.
Japanese Patent Publication No. 10-302291, Japanese Patent Publication No. 2000-2000
According to Japanese Patent Laid-Open No. 75130, there is proposed a structure in which a transparent substrate is provided with a birefringent film having a diffraction grating on the same plane, and an isotropic overcoat layer is coated or loaded on the birefringent film. Among these, there is one having a structure intended to improve the flatness of both surfaces in order to obtain good optical characteristics. This is because a birefringent film with a diffraction grating formed on the same plane is adhered with an adhesive on a transparent substrate such as glass or plastic, and the birefringent film is covered with an overcoat layer made of an isotropic adhesive. Since the layer also serves as an adhesive layer and is adhered to the opposing transparent substrate, the device has strength and is highly productive.

[0003]

That is, in this type of polarization separation element, in order to separate two orthogonal polarization components, the refractive index is different on the vibrating surface of different incident light on the transparent substrate. The anisotropic film is formed as a diffraction grating having a periodic uneven shape. Then, the step of filling the concave portion of the diffraction grating with an isotropic adhesive to form the overcoat layer and the step of adhering the counter transparent substrate on this overcoat layer are performed in the same step, and then each is diffracted. It is designed to be cut out into an element shape including a grating to complete each polarization separation element.

In order to form an overcoat layer by filling an isotropic adhesive in the concave portion of the uneven diffraction grating having a width of 3 μm and a depth of 5 μm in the above process, As the isotropic adhesive, it is desirable that the viscosity is low for easy filling.

However, when a low-viscosity isotropic adhesive is used, it is easy to embed it in the recessed portion because of its high fluidity, but at the same time, the flow in the lateral (planar) direction is also facilitated, resulting in overflow. It becomes extremely difficult to bond the coating layer to the opposing transparent substrate in a state where the thickness of the coating layer is uniform over a certain thickness.
Due to the structure, the overcoat layer also needs to function as an adhesive layer with the opposing transparent substrate, but if the thickness of the adhesive layer is non-uniform, the partial adhesive strength and the flatness will deteriorate. Occurs. In particular, when a polymer film is used as the birefringent film, the thickness of the adhesive layer and the adhesive strength are closely related, and it is empirically found that if the thickness of the adhesive layer is insufficient, the adhesive strength will be significantly reduced. Are known. Further, the thickness of the adhesive layer is important in the adhesion of a polymer film having poor adhesion. In addition, variations in the thickness of the adhesive layer cause variations in the thickness of the entire element, which causes deterioration of optical characteristics.

Further, when the adhesive interface between the transparent substrate and the opposing transparent substrate is non-tacky, the isotropic adhesive penetrates into this interface, and there is a problem that the thickness of the overcoat layer cannot be controlled.

Therefore, according to the present invention, the thickness of the overcoat layer formed by the isotropic adhesive for adhering the opposing transparent substrate and the transparent substrate can be made uniform to a desired thickness, and the flatness can be improved with high productivity. It is an object of the present invention to provide a method for manufacturing a polarization separation element that can manufacture a good polarization separation element.

Further, the present invention provides a method for producing a polarization separation element, which can prevent the isotropic adhesive from penetrating into the non-adhesive interface and ensure the thickness uniformity of the overcoat layer. The purpose is to do.

Further, the present invention provides a method for manufacturing a polarization beam splitting element capable of ensuring adhesive strength in order to achieve these objects.

Further, in order to achieve these objects, the present invention provides a low-cost method of manufacturing a polarization separation element capable of ensuring the adhesive strength of a difficult-to-adhere material such as a polymer material.

Furthermore, the present invention provides a method for manufacturing a polarization separation element capable of controlling the film thickness of the overcoat layer with high accuracy in order to achieve these objects.

Furthermore, the present invention provides a method for manufacturing a polarization beam splitting element, which can reduce the size and cost of the polarization beam splitting element in order to achieve these objects.

[0013]

The invention according to claim 1 is
In order to separate two orthogonal polarization components, an anisotropic film having a different refractive index with respect to a vibrating surface of different incident light is formed as a diffraction grating having a periodic uneven shape on a transparent substrate, and the concave portion of the diffraction grating is formed. A polarizing plate containing a diffraction grating as an element component, in which the step of forming an overcoat layer by filling with an isotropic adhesive and the step of adhering a counter transparent substrate on the overcoat layer are performed in the same step. In the method for manufacturing a separation element, a thickness regulating member that regulates the thickness of the overcoat layer by the isotropic adhesive that adheres the opposing transparent substrate and the transparent substrate is preliminarily provided outside the element in which the diffraction grating is formed. I set it up.

Therefore, a thickness regulating member for regulating the thickness of the overcoat layer made of an isotropic adhesive for adhering the opposing transparent substrate and the transparent substrate is provided in advance outside the element in which the diffraction grating is formed. Even when a viscosity isotropic adhesive is used, the thickness of the overcoat layer can be easily made uniform to a desired thickness, and the uniformity of the function as a polarization separation element can be improved. Further, by making the thickness uniform, the adhesive strength can be made uniform, and the polarization separation element having excellent productivity and high reliability can be manufactured.

According to a second aspect of the present invention, in the method for manufacturing a polarization beam splitting element according to the first aspect, an adhesive adhesive is used as the thickness regulating member.

Therefore, by using the sticky adhesive as the thickness regulating member, it is possible to prevent the isotropic adhesive forming the overcoat layer from penetrating into the adhesive interface, and to make the thickness of the overcoat layer uniform. The property can be secured with good controllability.

According to a third aspect of the present invention, in the method of manufacturing the polarization beam splitting element according to the second aspect, the opposing surface of the isotropic adhesive is opposed to the isotropic adhesive by the adhesive before the diffusion of the isotropic adhesive into the adhesive area. The transparent substrate and the transparent substrate were bonded together.

Therefore, before the isotropic adhesive is diffused in the tacky adhesive region, the opposing transparent substrate and the transparent substrate are bonded with the tacky adhesive to form an overcoat layer. The agent can be reliably prevented from penetrating into the adhesive interface, and the uniformity of the thickness of the overcoat layer can be secured with better controllability.

According to a fourth aspect of the present invention, in the method for producing a polarization beam splitting element according to the second or third aspect, the thickness of the adhesive adhesive is 30 μm or more and 100 μm or less.

Therefore, the adhesive strength of the hard-to-adhere material such as a polymer material is improved. That is, when the thickness is less than 30 μm, not only the production of a pressure-sensitive adhesive such as a double-sided pressure-sensitive adhesive sheet becomes expensive, but also the handling (handling) property deteriorates, which makes it difficult to control the thickness of the pressure-sensitive adhesive and results in over Variations occur in the thickness of the coat layer, and also
When the thickness of the overcoat layer is thin, the adhesive strength may be lowered, while when it is thicker than 100 μm, the amount of the isotropic adhesive to be filled is increased and the productivity is lowered.
By setting the thickness of the tacky adhesive to be 30 μm or more and 100 μm or less, such a problem can be avoided.

According to a fifth aspect of the present invention, in the method for manufacturing a polarization beam splitting element according to the second, third or fourth aspect, the sheet-like or tape-like double-sided adhesive having the adhesive adhesive cut out into an adhesive shape. It is an adhesive.

Therefore, the adhesive strength of the hard-to-adhere material such as a polymer material can be secured, and an industrial double-sided pressure-sensitive adhesive sheet can be used, so that the cost can be reduced.

According to a sixth aspect of the present invention, in the method for manufacturing a polarization beam splitting element according to the fifth aspect, the sheet- or tape-shaped double-sided adhesive adhesive cut out into an adhesive shape has an initial thickness after pressure curing. Is thicker than the thickness of the overcoat layer.

Therefore, the thickness of the overcoat layer can be reliably regulated to a predetermined thickness by a sheet-shaped or tape-shaped double-sided adhesive agent, and highly accurate film thickness control of the overcoat layer becomes possible. Become.

The invention according to claim 7 is the invention according to claims 2 to 6.
In the method for manufacturing a polarization beam splitting element according to any one of the above items, a part of the adhesive adhesive previously provided outside the element on which the diffraction grating is formed is open.

Therefore, even if there is a surplus adhesive in the isotropic adhesive, the thickness of the overcoat layer is reliably regulated to a predetermined thickness by causing the adhesive adhesive to flow out from the open portion. It is possible to control the film thickness of the overcoat layer with high accuracy.

The invention according to claim 8 is the invention according to claims 2 to 6.
In the method for manufacturing a polarization beam splitting element according to any one of the above, the adhesive adhesive is provided outside the element so as to surround each element in the element unit in which the diffraction grating is formed.

Therefore, a tacky adhesive may be provided outside the elements so as to surround the entire plurality of elements on which the diffraction grating is formed. However, when the individual elements are independent, each element is separated into individual elements. By providing an adhesive adhesive outside the element to surround it,
It is possible to effectively control the film thickness of the overcoat layer for each element.

The invention according to claim 9 is the invention according to claims 1 to 8.
In the method for manufacturing a polarization beam splitting element according to any one of items 1 to 3, the isotropic adhesive is made of a photo-curing acrylic or epoxy material.

Therefore, by using a photocurable acrylic or epoxy material as the isotropic adhesive, it is possible to reduce the cost of the polarization separation element produced.

According to a tenth aspect of the present invention, in the method for manufacturing a polarization beam splitting element according to the ninth aspect, the isotropic adhesive is supplied in a larger amount than the volume for filling and adhering.

Therefore, by supplying the isotropic adhesive in an amount larger than the volume for filling and adhering and regulating the film thickness by the thickness regulating member such as the tacky adhesive, the isotropic adhesive becomes insufficient and a predetermined amount is obtained. A uniform film thickness can be specified without becoming thinner than the thickness.

The invention according to claim 11 is the invention according to claim 9 or 1.
In the method for producing a polarization beam splitting element according to item 0, the isotropic adhesive is supplied into the adhesive region formed by the adhesive.

Therefore, the isotropic adhesive can be regulated to have a uniform film thickness without waste.

According to a twelfth aspect of the present invention, in the method of manufacturing a polarization beam splitting element according to any one of the first to eleventh aspects, the diffraction grating is formed of a polymer birefringent film.

Therefore, since the diffraction grating is formed of the polymer birefringent film, it is possible to reduce the cost of the polarization separation element to be manufactured.

According to a thirteenth aspect of the present invention, in the method for producing a polarization beam splitting element according to the twelfth aspect, the polymer birefringent film is a polymer film in which molecular chains are oriented by stretching.

Therefore, since the polymer birefringent film forming the diffraction grating is formed of the polymer film in which the molecular chains are oriented by stretching, the cost of the polarization separation element to be manufactured can be reduced. .

According to a fourteenth aspect of the present invention, in the method of manufacturing a polarization beam splitting element according to any one of the first to eleventh aspects, the diffraction grating is formed of a polymer film in which molecular chains are oriented.

Therefore, since the diffraction grating is formed by the polymer film in which the molecular chains are oriented, it is possible to reduce the cost of the polarization separation element to be manufactured.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention.
Or, it demonstrates based on FIG.

[Outline] The structure of the polarization beam splitting element 1 of the present embodiment is, for example, as shown in FIG. 1, a polymer compound in which a diffraction grating 3 is formed on the same plane of a transparent substrate 2. The refraction film 4 is adhered via the adhesive layer 5, and the overcoat layer 6 in which isotropic adhesive is filled between the recesses of the diffraction grating 3 also functions as an adhesive layer and is adhered to the counter transparent substrate 7. It is a polarization separation element having a configuration.

In producing the polarization beam splitting element 1 including such a diffraction grating 3 as an element constituent element, a step of forming an overcoat layer 6 by filling the recessed portion of the diffraction grating 3 with an isotropic adhesive. The step of adhering the counter transparent substrate 7 on the overcoat layer 6 is performed in the same step, and thereafter, the element shape including each diffraction grating is cut out to complete each polarization separation element. In the form of, the adhesiveness is different from the isotropic adhesive used for the overcoat layer outside the element formation region of the polymer birefringent film in which the diffraction grating is formed to make the thickness of the overcoat layer uniform. The thickness of the overcoat layer is controlled by providing a so-called double-sided pressure-sensitive adhesive sheet, which is a double-sided pressure-sensitive adhesive sheet having a total thickness controlled by applying an adhesive having the above-mentioned to the support substrate. The shape of this sticky adhesive is formed so as to surround the outside of the element region where the diffraction grating is formed, but a part of it is open so that excess adhesive may flow out of the adhesive region. I have to.

[Specific Configuration Example] An example of a method of manufacturing the polarization beam splitting element of the present embodiment will be described with reference to FIGS. First, as shown in FIG. 2, BK-7 (transparent substrate) 8 having a diameter of 4 inches and a thickness of 1.0 mm was optically polished on both sides, and then an antireflection film 9 was formed on one side so that the incident wavelength 660 nm was minimized. A polymer birefringent film 1 having a diameter of 5 inches and a thickness of 200 μm is formed on the back surface of the BK-7 (transparent substrate) 8.
0 with an acrylic resin-based photocurable adhesive 11
The polymer birefringent film 10 was cut along the φ4 inch BK-7 (transparent substrate) 8 to obtain the transparent substrate 8. A specific method of this adhesion will be described later with reference to FIGS. 8 and 9.

The polymer birefringent film 10 adhered to the transparent substrate 8 is washed with an organic solvent such as isopropyl alcohol and pure water. Thereafter, a ZEP-520 resist manufactured by Nippon Zeon Kabushiki Kaisha is spin-coated to form a resist film having a thickness of 0.5 μm, and after baking, a stepper device manufactured by Nikon Corporation is used to form a line and space pattern of 5 μm within a range of φ90 mm. , ECR (Electron Cyclotron Resonan) manufactured by Sumitomo Metals in an etching gas atmosphere containing oxygen gas as a main component.
ce: Electron cyclotron resonance) etching equipment with a width of 3μ
m, depth 5μm line and 3μm width space 300
Diffraction grating 12 that was repeated periodically was formed (see FIG. 3).
A plurality of the diffraction gratings 12 are formed in order for the plurality of polarization separating elements in order to manufacture the plurality of polarization separating elements 13 in one manufacturing process (see FIG. 4). Due to the handling of each device, the effective element formation range is φ80m.
Within m.

The other photolithography process adopts a generally known process, and its details are omitted.

On the surface of the polymer birefringent film 10 on which the diffraction grating 12 is formed, as shown in FIG.
An industrial double-sided pressure-sensitive adhesive sheet having a thickness of 50 μm and having an inner diameter of 85 mm is provided in a region of 80 mm or more that does not affect the (polarization separating element 13).
mm, outer diameter φ95 mm, cut out and bonded with a circular cutter, and have openings 1 with a width of 1 mm in three 120 ° equal parts.
4 is provided, and the thickness regulating member 15 is made of an adhesive.

Next, as shown in FIG. 5, the transparent substrate 8
Is placed on a stainless steel table 16 having a surface of φ200 mm and a thickness of 50 mm, and an acrylic resin-based photo-curing isotropic adhesive 17 is predetermined in the center of the polymer birefringent film 10 on which the diffraction grating 12 is formed. 0.27 ml, which is a 20% increase in the filling amount, was measured and dropped by a microsyringe, and BK-7 having both sides optically polished on the transparent substrate 8 had an outer diameter of 4 inches and a thickness of 1.
A 0 mm counter transparent substrate 18 is placed, and an optically polished quartz glass is placed as a pressure device 19 on the counter transparent substrate 18, and a pressure of 100 gf / cm ² is applied to the counter transparent substrate 18, and the isotropic adhesive 17 is adhered. Spread it all over.

Since the thickness of the thickness regulating member 15 made of the double-sided pressure-sensitive adhesive sheet is thicker than the target thickness, the double-sided pressure-sensitive adhesive sheet (thickness regulating member 15) and the opposing transparent substrate 18 are first bonded by pressure. The surplus adhesive sticks out from the opening 14 of the double-sided pressure-sensitive adhesive sheet (thickness regulating member 15).
The thickness of the double-sided pressure-sensitive adhesive sheet (thickness regulating member 15) is determined according to the pressure. In this state, the transparent substrate 18, 8 was irradiated with ultraviolet light having an irradiance of 20 mW / cm ² from the upper surface of 150 mm by an ultraviolet irradiation device (not shown) for 20 minutes to cure and bond the isotropic adhesive 17 as the overcoat layer. FIG. 6 shows a sectional structure after curing and adhesion.

An antireflection film 9 is formed on the non-adhesive surface of the transparent substrate 8 so that the incident wavelength of 660 nm is minimized.

Next, the element 13 having the diffraction grating 12 formed thereon was cut into a size of 4 mm × 4 mm by a dicing device. The individual elements 13 thus cut out become the polarization splitting element 1 as shown in FIG. Transparent substrate 8 is transparent substrate 2, diffraction grating 12 is diffraction grating 3, and polymer birefringent film 1
0 is the polymer birefringent film 4, the adhesive 11 is the adhesive layer 5, the overcoat layer 17 is the overcoat layer 6, and the counter transparent substrate 1
8 correspond to the opposing transparent substrate 7, respectively.

In this embodiment, the double-sided pressure-sensitive adhesive sheet having a thickness of 50 μm was used to obtain the overcoat layer 17 having a thickness of up to 40 μm. However, the thickness of the double-sided pressure-sensitive adhesive is not limited to 50 μm. The thickness is 30 μm or more 100
It is preferably not more than μm, more preferably 30
It is preferably not less than μm and not more than 50 μm. That is, if the thickness is less than 30 μm, not only the production of the double-sided pressure-sensitive adhesive sheet becomes expensive, but also the handling (handling) property deteriorates, which makes it difficult to control the thickness of the pressure-sensitive adhesive, and as a result, the thickness of the overcoat layer 17 varies. Occurs. Further, if the thickness of the overcoat layer 17 is reduced, the adhesive strength may be reduced. On the other hand, when it is thicker than 100 μm, the amount of the overcoat agent to be filled increases and the productivity decreases.

When the thickness of the overcoat layer produced by changing the thickness of the double-sided pressure-sensitive adhesive sheet was measured, the thickness of the overcoat layer was obtained almost according to the thickness of the double-sided pressure-sensitive adhesive sheet. As shown in FIG. 7, the result is that the overcoat layer is thin with respect to the thickness of the tacky adhesive as a whole.

Further, the thickness regulating member 15 for regulating the thickness of the isotropic adhesive 17 may be printed by a method other than using the double-sided pressure-sensitive adhesive sheet shown in the present embodiment. Further, as the isotropic adhesive 17 of the polarization beam splitting element 13, an acrylic adhesive is used in terms of the ease of controlling the characteristics such as viscosity and refractive index, the adhesive strength and the transparency, but the same can be applied to the epoxy adhesive. It is possible. Since these adhesives are cured by ultraviolet rays (photo-curing type), they can be cured under pressure and the process is simplified.

The polymer birefringent film 10 is formed by rubbing a polymer film such as polyethylene terephthalate with a cloth to rub it to form an alignment film, and then polydiacetylene monomer is vacuum-deposited on the alignment film to align it. Method of polymerizing by irradiation with ultraviolet light to form an anisotropic film (reference: J.Appl.phy
s., 72, No, 3, P938-947), but in the present embodiment,
A stretched organic polymer film was used in which the molecular chains were oriented and the property was taken into consideration.

By the way, in FIG. 2, a polymer birefringent film 10 having a diameter of 5 inches and a thickness of 200 μm is adhered to the back surface of the above-mentioned BK-7 (transparent substrate) 8 with an acrylic resin-based photocurable adhesive 11. A manufacturing step of cutting the polymer birefringent film 10 along the φ4 inch BK-7 (transparent substrate) 8 to form the transparent substrate 8,
Particularly, the bonding step will be described in more detail.

As shown in the cross-sectional structure diagram of FIG. 8, the antireflection film 9 (in order to minimize the incident wavelength of 660 nm on one surface of the BK-7 (transparent substrate) 8 having a diameter of 4 inches and a thickness of 1.0 mm and which is optically polished. (See FIG. 2) to form a transparent substrate.
A polyester λ / 4 plate (hereinafter referred to as a λ / 4 film) is used as a polymer birefringent film 10 having a diameter of 5 inches and a thickness of 200 μm on the surface of the transparent substrate 8 on which the antireflection film 9 is not formed, which is an acrylic resin photocurable type. The adhesive 11 is used to adhere to the transparent substrate 8.

This BK-7 (transparent substrate) 8 has a thickness of 30 μm.
The double-sided adhesive sheet, which is the adhesive adhesive 21 of m, has an inner diameter of φ8.
Cut out and bond in a ring shape with a diameter of 5 mm and an outer diameter of 95 mm,
An opening having a width of 1 mm was provided at three locations equally divided by 120 ° to obtain a bonding thickness defining member (bonding thickness defining member 1 in the case of FIG. 4).
Same as 5.). In addition, double-sided adhesive sheet (adhesive adhesive 2
1) is attached to a Φ / 4 film (polymer birefringent film 10) in a φ80 mm region that does not affect the element.

Next, a polyester-based λ / 4 film cut into φ5 inch was subjected to optical plane processing, and the diameter was 200 mm.
Quartz glass 23 having a vacuum suction port 22 with a thickness of 50 mm
It was placed with the central axes aligned with each other, and the outside of the bonding range of the λ / 4 film was fixed by vacuum suction by a vacuum exhaust device (not shown). Next, an acrylic resin-based photo-curing isotropic adhesive 17 is added to this central portion by a 20% increase of a predetermined filling amount of 0.1.
2 ml was measured with a microsyringe and added dropwise. This λ /
The above-mentioned transparent substrate 8 was placed on the 4 film, a pressure of 100 gf / cm ² was applied by the pressure device 24, and the isotropic adhesive 17 was spread over the entire surface to be adhered.

Here, the thickness of the double-sided pressure-sensitive adhesive sheet 21 is thicker than the target thickness, and the double-sided pressure-sensitive adhesive sheet 21 and the transparent substrate 8 are first bonded to each other by applying pressure. The surplus adhesive sticks out from the opening of the double-sided adhesive sheet 21. The pressure is regulated by the thickness of the double-sided pressure-sensitive adhesive sheet 21.
The isotropic adhesive 1 was obtained by irradiating the transparent substrate 8 with ultraviolet light having an illumination intensity of 10 mW / cm ² from the 0 mm upper surface for 10 minutes.
7 was cured and adhered.

After that, as shown in FIG. 9, the λ / 4 film 10 was cut along the φ4 inch transparent substrate 8. As a result, the transparent substrate 8 as shown in FIG. 2 is obtained.

A second embodiment of the present invention will be described with reference to FIGS. The same reference numerals are used for the parts shown in the above-mentioned embodiments, and the description is omitted.

Basically, it is the same as the above-described embodiment, but in this embodiment, it is out of the formation range of the individual elements 13 of the polymer birefringent film 10 in which a plurality of diffraction gratings 12 are formed. An adhesive is provided as the thickness regulating member 31. Specifically, a UV-curable adhesive is screen-printed in a grid pattern with some corners open to a width of 1 mm and a thickness of 30 μm.
m pattern.

Next, the adhesive as the thickness regulating member 31 was irradiated with ultraviolet light at a light amount of about 80% of the complete curing condition, so that the surface was in a semi-solid state having tackiness. In this embodiment mode, the element shape is a square and each corner is open, but the element shape is not limited to a square, and may be a circle, a triangle, a hexagon, or the like, a part of which is shown in FIG. It is sufficient that the surplus adhesive has a passage (opening) 32 that flows to the outside. Further, this time, the curing condition of the ultraviolet curable adhesive was devised and used.
Since it is out of the forming range and the optical characteristics of the element 13 are not restricted, a commonly used tacky adhesive may be used.

An isotropic adhesive 17 is applied to the center of this pattern.
6x10 with a 20% increase in the prescribed filling amount with a microsyringe
^{After -5} ml was dropped, the transparent substrate 8 was subjected to optical plane processing in the same manner as described with reference to FIG. 8, φ200 mm, thickness 50 mm.
The quartz glass is placed with its central axis aligned, fixed by vacuum suction through a vacuum suction port, and the opposing transparent substrate 18 is bonded and pressure-bonded according to the alignment mark provided on each. At this time, the surplus adhesive passes through the opening 32 and flows into the space portion of the adhesive pattern that defines the thickness. Thereafter, the steps of curing by irradiation with ultraviolet light and cutting into elements are the same as in the case of the first embodiment. FIG. 12 shows the cross-sectional structure of the element after curing and adhesion.

[0066]

According to the first aspect of the present invention, in order to separate two orthogonal polarization components, an anisotropic film having a different refractive index is periodically provided on the vibrating surface of different incident light on the transparent substrate. The step of forming an overcoat layer by forming a concave and convex diffraction grating and filling an indented portion of the diffraction grating with an isotropic adhesive is the same as the step of adhering a counter transparent substrate on the overcoat layer. In a method for manufacturing a polarization separation element including a diffraction grating as an element component, which is performed in the step,
By providing a thickness regulating member that regulates the thickness of the overcoat layer, which is an isotropic adhesive that bonds the opposing transparent substrate and the transparent substrate, outside the element on which the diffraction grating is formed, isotropic with low viscosity is obtained. Even when using an adhesive, the thickness of the overcoat layer can be easily made uniform to a desired thickness,
It is possible to improve the uniformity of the function as a polarization separation element, and also to make the adhesive strength uniform by making the thickness uniform, which is excellent in productivity and reliability. Can be produced.

According to the invention described in claim 2, in the method for producing a polarization beam splitting element according to claim 1, an isotropic adhesive for forming an overcoat layer by using a tacky adhesive as a thickness regulating member. Can be prevented from penetrating into the adhesive interface, and the uniformity of the thickness of the overcoat layer can be ensured with good controllability.

According to the invention described in claim 3, in the method for manufacturing the polarization beam splitting element according to claim 2, before the isotropic adhesive is diffused in the adhesive adhesive region, the transparent opposite surface is formed by the adhesive adhesive. By bonding the substrate and the transparent substrate, it is possible to reliably prevent the isotropic adhesive that forms the overcoat layer from penetrating into the adhesive interface, and to control the uniformity of the thickness of the overcoat layer more easily. Can be secured well.

According to the invention described in claim 4, in the method for manufacturing the polarization beam splitting element according to claim 2 or 3, the thickness of the adhesive is 30 μm or more and 100 μm or less.
It is possible to improve the adhesive strength of difficult-to-adhere materials such as polymer materials. That is, if the thickness is less than 30 μm, not only the production of an adhesive adhesive such as a double-sided adhesive sheet becomes expensive, but also
Since the handling property decreases, it becomes difficult to control the thickness of the adhesive adhesive, and as a result, the thickness of the overcoat layer varies, and when the thickness of the overcoat layer decreases, the adhesive strength decreases. On the other hand, if the thickness is more than 100 μm, the amount of the isotropic adhesive to be filled will increase and the productivity will decrease. However, if the thickness of the adhesive adhesive is 30 μm or more and 100 μm or less, It is possible to avoid such a defect.

According to the invention of claim 5, claim 2
In the method for producing a polarization separation element according to 3 or 4, by using a sheet-like or tape-like double-sided adhesive adhesive cut out in an adhesive shape as the adhesive adhesive, a difficult-to-adhere material such as a polymer material While ensuring the adhesive strength of
Since an industrial double-sided pressure-sensitive adhesive sheet or the like can be used, the cost can be reduced.

According to the sixth aspect of the invention, in the method for producing the polarization beam splitting element according to the fifth aspect, the initial thickness of the sheet- or tape-shaped double-sided adhesive adhesive cut out in the adhesive shape is pressed. Since it is thicker than the thickness of the overcoat layer after curing, the thickness of the overcoat layer can be reliably regulated to a predetermined thickness with a double-sided adhesive sheet or tape. Accurate film thickness control becomes possible.

According to a seventh aspect of the invention, in the method for manufacturing the polarization beam splitting element according to any one of the second to sixth aspects, the adhesive adhesive is provided in advance outside the element on which the diffraction grating is formed. Since a part of the adhesive is open, even if there is excess adhesive in the isotropic adhesive, the thickness of the overcoat layer can be surely adjusted to a predetermined value by allowing the adhesive adhesive to flow out from the open portion. The thickness can be regulated, and the overcoat layer can be precisely controlled in thickness.

According to the invention described in claim 8, in the method for manufacturing the polarization beam splitting element according to any one of claims 2 to 6, the element is adhered to the outside of the element so as to surround the entire plurality of elements in which the diffraction grating is formed. Although an adhesive adhesive may be provided, if individual elements are independent, by providing an adhesive adhesive outside the element so that each element is surrounded by each element, it is possible to effectively cover each element. The film thickness of the coat layer can be controlled.

According to a ninth aspect of the present invention, in the method for producing a polarization beam splitting element according to any one of the first to eighth aspects, a photocurable acrylic or epoxy material is used as the isotropic adhesive. By using it, it is possible to reduce the cost of the manufactured polarization separation element.

According to the invention of claim 10, claim 9 is provided.
In the method for manufacturing the polarization separation element described, by supplying a larger amount than the volume for filling and adhering the isotropic adhesive to define the film thickness with a thickness regulating member such as an adhesive adhesive, the isotropic adhesive is It is possible to define a uniform film thickness without being insufficient and being thinner than a predetermined thickness.

According to the invention of claim 11, claim 9 is provided.
Alternatively, in the method for manufacturing a polarization beam splitting element according to item 10, by supplying the isotropic adhesive into an adhesive region formed by the adhesive, the isotropic adhesive has a uniform film thickness without waste. Can be specified in.

According to the invention of claim 12, claim 1
In the method for manufacturing a polarization beam splitting element according to any one of items 1 to 11, since the diffraction grating is formed of a polymer birefringent film, the cost of the polarization beam splitting element to be manufactured can be reduced.

According to the invention of claim 13, claim 1
In the method for producing a polarization separation element according to the item 2, the cost of the polarization separation element to be produced is low because the polymer birefringent film forming the diffraction grating is formed of a polymer film in which molecular chains are oriented by stretching. Can be realized.

According to the invention of claim 14, claim 1
In the method for manufacturing a polarization separation element according to any one of 1 to 11, since the diffraction grating is formed of a polymer film in which molecular chains are oriented, the cost of the polarization separation element to be manufactured can be reduced. .

[Brief description of drawings]

FIG. 1 shows a polarization beam splitting element according to a first embodiment of the present invention, in which (a) is a schematic sectional view and (b) is a schematic plan view thereof.

FIG. 2 is a schematic cross-sectional view showing one step in the manufacturing process.

FIG. 3 is a schematic cross-sectional view showing a manufacturing process of the diffraction grating during the manufacturing process.

FIG. 4 is a schematic plan view showing a manufacturing process of the thickness regulating member during the manufacturing process.

FIG. 5 is a schematic cross-sectional view showing an adhering step using a sticky adhesive during a manufacturing step.

FIG. 6 is a schematic cross-sectional view showing a state after adhesion with a sticky adhesive during a manufacturing process.

FIG. 7 is a characteristic diagram showing characteristics of tacky adhesive-overcoat layer thickness.

FIG. 8 is a schematic cross-sectional view showing a step of adhering a polymer birefringent film to a transparent substrate.

FIG. 9 is a schematic cross-sectional view showing the state after the bonding.

10A and 10B show a manufacturing method according to a second embodiment of the present invention, FIG. 10A is a schematic plan view, and FIG.

FIG. 11 is a schematic plan view showing the flow of excess adhesive.

FIG. 12 is a schematic cross-sectional view showing after bonding.

[Explanation of symbols]

8 transparent substrate 10 Polymer birefringent film 12 diffraction grating 13 elements 14 openings 15 Thickness regulating member, adhesive 17 Isotropic adhesive 18 Opposite transparent substrate 31 Thickness regulating member, adhesive adhesive

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H049 AA03 AA13 AA31 AA33 AA37                       AA45 AA48 AA65 BA05 BA42                       BA45 BB52 BC03 BC08 BC14

Claims (14)

[Claims] 1. An anisotropic film having a different refractive index with respect to a vibrating surface of different incident light is formed on a transparent substrate as a diffraction grating having a periodic concavo-convex shape in order to separate two orthogonal polarization components. A diffraction grating element in which the step of forming an overcoat layer by filling an isotropic adhesive in the concave portion of the diffraction grating and the step of adhering a counter transparent substrate on this overcoat layer are performed in the same step In the method for manufacturing a polarization separation element included in the constituent elements, the diffraction grating is formed with a thickness defining member that defines the thickness of the overcoat layer by the isotropic adhesive that bonds the opposing transparent substrate and the transparent substrate. A method for manufacturing a polarization beam splitting element, characterized in that it is provided outside the element in advance. 2. The method for manufacturing a polarization beam splitting element according to claim 1, wherein a tacky adhesive is used as the thickness regulating member. 3. The adhesive substrate is used to bond the opposing transparent substrate and the transparent substrate before the isotropic adhesive is diffused in the adhesive region. Item 3. A method for manufacturing a polarization separation element according to item 2. 4. The thickness of the adhesive adhesive is 30 μm or more and 100 μm or less.
A method for producing the polarization splitting element described. 5. The polarization separating element according to claim 2, 3 or 4, wherein the adhesive adhesive is a sheet-like or tape-like adhesive having double-sided adhesive cut out in an adhesive shape. Method. 6. The sheet-shaped or tape-shaped double-sided adhesive adhesive cut out in an adhesive shape has an initial thickness larger than that of the overcoat layer after pressure curing. A method for manufacturing a polarization separation element. 7. The polarization beam splitting element according to claim 2, wherein a part of the adhesive adhesive provided in advance outside the element on which the diffraction grating is formed is open. Of manufacturing. 8. The device according to claim 2, wherein the adhesive agent is provided outside the element so as to surround each element in the element in which the diffraction grating is formed. A method for manufacturing a polarization separation element. 9. The method for producing a polarization beam splitting element according to claim 1, wherein the isotropic adhesive is made of a photo-curing acrylic or epoxy material. 10. The method for manufacturing a polarization beam splitting element according to claim 9, wherein the isotropic adhesive is supplied in a larger amount than the volume for filling and adhering. 11. The method of manufacturing a polarization beam splitting element according to claim 9, wherein the isotropic adhesive is supplied into an adhesive region formed by the adhesive adhesive. 12. The method for manufacturing a polarization beam splitting element according to claim 1, wherein the diffraction grating is formed of a polymer birefringent film. 13. The method for producing a polarization beam splitting element according to claim 12, wherein the polymer birefringent film is a polymer film in which molecular chains are oriented by stretching. 14. The method of manufacturing a polarization beam splitting element according to claim 1, wherein the diffraction grating is formed of a polymer film in which molecular chains are oriented.